Questions about Backflow?

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What is a Cross Connection?

A cross connection is a connection between a potable drinking water supply and a possible source of contamination or pollution.  Under the provisions of the Safe Drinking Water Act of 1971, the Environmental Protection Agency (EPA) established national standards for safe drinking water.  Each state is required to enforce the various regulations of the Safe Drinking Water Act and how it relates to it's laws.  

To meet these provisions, the Texas Commission on Environmental Quality (TCEQ) on Jan 1, 1996, enacted a state law which requires the public water suppliers to implement and enforce the Cross Connection Control Program requirements located in the Texas Administrative Code (TAC), Title 30, Chapter 290 of the Rules and Regulations for Public Water Suppliers.

What is Backflow?

Backflow is the undesirable reversal of flow in a potable water distribution system.  If water that is always under pressure can only flow in one direction, then how can water flow in reverse?  Water will always flow towards the point of the lowest pressure.  If a water main were to break or if the fire department opens a fire hydrant, the pressure in the water main could drop.  The demand upstream could cause a reversal in flow.  

Cross connections and the possibility of a backflow need to be recognized so they do not occur.  A garden hose submerged in a tub, swimming pool, car radiator or attached to an insect/herbicide sprayer could siphon the liquid back into the water main.  Water from an irrigation system could be siphoned back into the public water supply.  Backflow prevention assemblies are designed to protect the public water system from these types of concerns.  

Testing of Backflow Prevention Assemblies.  

All backflow protection assemblies must be tested upon installation, repair or relocation.  Because backflow prevention assemblies are mechanical devices that will degrade over time, all backflow assemblies should be tested annually to ensure they are in working order.